What is considered normal and average oil consumption for a '90 190E 2.6?

My last oil change was about 2100 miles ago, and I have not had to add any oil, yet. But that is not to say the oil level didn't go down. Last time I checked (5/22/00), the level was slightly below the upper red mark (approx. 3mm).

One last question, between the MIN and MAX mark, how many quarts of oil is that?

It seems like 3mm might be able to be accounted for by thermal expansion if, for example, you checked it cold one time and hot another time. I think most cars are about a quart between MIN and MAX. Are there oil spots under your car if you park it somewhere for a long time?